The new Oliver Stone stoner film, Savages, opens today, July 6. It’s based on Don Winslow’s 2010 novel, but I’ve noticed in reviews that John Travolta has a line about marijuana that isn’t in the book: “This stuff’ll be legal in three years,” he says. “Embrace the change.” It’s an apt update.

Travolta, mind you, doesn’t play some wishful-thinking pothead. His character is a corrupt federal anti-drug agent who, in the novel, seems burned out on the futile task of marijuana interdiction. He’s just as weary of watching the ghastly violence, both in Mexico and the U.S., that results from the illegal trafficking of a multi-billion-dollar drug that at least half of America now believes should be legal. Our largest cities appear to believe it too, including New York, where police have been told they should no longer arrest people found in possession of small amounts of pot; and Chicago, where last month the city council voted resoundingly to let cops give most marijuana violators tickets instead of handcuffs so they can focus on more important crime-fighting targets.

Given Stone’s penchant for unhinged narco-mayhem, Savages is likely to illustrate, as the book did, why keeping weed illegal no longer makes legal, fiscal or even moral sense. Mexico’s powerful and vicious drug cartels – one of which is depicted in Savages as muscling in on a thriving clandestine pot business run by two buddies in California – earn more than $30 billion a year trafficking drugs into the U.S., and marijuana accounts for as much as half of that. Which means illicit cannabis cash is responsible in no small part for the more than 55,000 drug-related murders in Mexico since 2006, including the kind of macabre cartel massacres and beheadings that in Winslow’s story (if not necessarily in real life) seem poised to spill across the border.

Decriminalizing marijuana, a drug widely considered no more harmful than alcohol or tobacco when consumed moderately, is one sound way of depriving the traffickers of their revenue and the monstrous arsenals it buys. I don’t smoke the stuff myself, so I don’t have a dope dog in this fight; and I don’t support the legalization of harder, genuinely ravaging drugs like cocaine. But Savages is a useful pop-culture reminder of the absurd, Prohibition-style tragedy that conventional drug-war thinking on marijuana has brought us to. Criminalization too often means that production and sale are in the hands of quasi-degenerates like Winslow’s protagonists, Ben and Chon (OK, they help Third World kids; so did Pablo Escobar) or homicidal psychopaths like Elena and Lado, the Mexican cartel’s queen and her enforcer. Or weed-peddling street gangs in Chicago, where more people have been murdered this year than U.S. troops killed in Afghanistan.

And that’s only a part of the mess we’ve created. More than half the drug arrests U.S. law enforcement makes each year are marijuana-related – and almost 90% of those are for mere possession, which in lock-em-up states like Florida can get you a year in jail for an amount as small as 20 grams, or less than an ounce. In the end, the country squanders an incredible $8 billion a year busting and incarcerating marijuana users – a figure that climbs to $14 billion when you include the tax revenue to be gained if marijuana sales were legal and regulated. (Little wonder that 300 economists, including three Nobel laureates, called this year for marijuana legalization.) At the same time, there’s a clear racial component to wrestle with: while African-Americans represent only 14% of U.S. marijuana users, they account for 31% of marijuana arrests.

Even though the Obama Administration and much of the rest of Washington are sticking to their marijuana demonization script – especially in an election year – much of the rest of the country is moving beyond the Nixonian drug-war mindset. Colorado and Washington have put the marijuana legalization question on their November ballots. In Oregon, pro-legalization candidate Ellen Rosenblum won the Democratic primary for state Attorney General. (So far she’s running unopposed in the general election.) And in the recent Texas primary, pro-legalization candidate and former El Paso City Councilman Beto O’Rourke defeated an eight-term congressman and is almost assured a November victory in his heavily Democratic district.

It’s also fitting (despite the awful Spanish in Winslow’s novel) that Savages opens just days after Mexico elected a new President, Enrique Peña Nieto. This week Peña echoed most of his Latin American counterparts when he told PBS, and indirectly the White House, that the drug war is “not working.” While Peña said he doesn’t favor legalizing drugs himself – even if he did, no Mexican President is likely to say so given the $1.5 billion in interdiction aid the U.S. is sending south of the border – he did call for a hemispheric debate on drug-war strategy that includes legalization. Many U.S. officials worry that Peña intends to go soft on drug trafficking, as his Institutional Revolutionary Party (PRI) did in the 20th century when it last held Mexico’s presidency. He insists that isn’t true, although last month he told me that Mexico’s priority, more than reining in trafficking, “has to be reducing violence.” But the U.S. would do well to listen to Peña since the PRI isn’t as apt as his predecessor’s party to toe Washington’s drug war line.

Last month, Uruguay even proposed legalizing marijuana and making its government the drug’s sole seller. No one of course is suggesting the U.S. consider anything along those lines – that would be socialist. But if stories like Savages underscore anything, it’s that even government bureaucrats are preferable to ghastly butchers when it comes to dealing pot. It’s a change we’re ready to embrace.